Prismatic materials that capture and reflect light in different directions are known to convey the appearance of depth or three-dimensions on a flat surface. Such prismatic materials may utilize a Fresnel lens, which is a thin lens having multiple, stepped setbacks that effectively transform the thin lens into multiple lenses with optical properties associated with a much thicker lens.
More specifically, positive focal length Fresnel lenses are almost universally plano-convex originating from a planar side or face and a curved or aspheric side of a conventional lens. To produce the Fresnel lens, the bulk of material between the sides of the conventional lens is reduced by extracting a set of coaxial annular cylinders of material. The contour of the curved surface of the conventional lens is thus approximated by right circular cylindrical portions intersected by conical portions called xe2x80x9cgrooves.xe2x80x9d Near the center of the standard circular Fresnel lens, these inclined surfaces or xe2x80x9cgroovesxe2x80x9d are nearly parallel to the plane face; toward the outer edge, the grooves become extremely steep. The grooves thus correspond to a respective portion of the original curved or aspheric surface, which are translated into the piano surface and appear as the familiar xe2x80x9cjaggedxe2x80x9d Fresnel lens.
The Fresnel lens is often viewed in a circular shape, and when backed with a silver-colored material, for example, produces an image of a silver ball appearing to have three-dimensions. Prismatic material of this type is available as a repeating Fresnel pattern film laminate under the trademark Multi-Lens(trademark) by Coburn Corporation, Lakewood, N.J. Heretofore, such film laminates have been limited to simple circular shapes, for example, as a function of circular lathes typically used to produce the Fresnel-type dies used to make the film laminates.
By cutting portions of a circular Fresnel lens into star-shaped components and assembling the components into a star-shaped die, the present invention provides a novel star pattern having an optical illusion of three-dimensional (3-D) stars on a flat surface based on optical light reflection and Fresnel lens light diffraction principles.
A star shape requires substantially straight lines depending from a center of the star shape to obtain the proper light reflection for a 3-D illusion, which is explained in greater detail herein. Nevertheless, the present invention utilizes a lathe that rotates and cuts its products in a circular motion based on a cylindrical lathe diamond turning technique. Of course, other lathes may be used to produce products of the present invention.
By disposing relatively small star-shaped components on an outer edge of the cylindrical lathe""s cutting surface, multiple cuts are made on the star-shaped components. Due to the relative size of the star-shaped components, the cuts appear as substantially straight, parallel lines next to each other despite being made by the cylindrical lathe.
When fitted together, the star-shaped components form a star-shaped die, which is used to produce metallized film having 3-D stars or star patterns to cover and finish, for example, a decorative tissue box.
Accordingly, in one aspect of the invention, a method is disclosed for forming a star-shaped die to produce a star-shaped pattern exhibiting a three-dimensional (3-D) illusion. The steps of this method include:
providing a plurality of metal portions shaped as parts of a star;
placing the plurality of metal portions on an outer edge of a lathe;
turning the lathe and the plurality of metal portions to cut a plurality of substantially straight grooves in the plurality of metal portions with a cutter; and
removing the plurality of metal portions from the lathe and assembling the plurality of metal portions as a star-shaped die configured to form a master shim.
In this method for forming the star-shaped die, holding tools releasably hold the metal portions on the outer edge of the lathe during the cutting step. The grooves are cut in the metal portions by a diamond chip cutter in a circular motion on an arc of an outer edge of the lathe. Alternatively, a lathe can be used that is specifically designed to create straight line grooves.
In some ways similar to the foregoing aspect, the present invention discloses the star-shaped die itself. As suggested by the previous embodiment, the star-shaped die is configured for forming a star pattern to convey an impression of three-dimensions (3-D) on a flat surface.
The present invention provides in a further aspect a metallized rolled web product including an elastomeric base and a metal layer bonded to the elastomeric base. The metal layer and elastomeric base combine to appear as a metallic film exhibiting a plurality of stars, each of the stars having a plurality of grooves, at least one of the plurality of grooves depending substantially straight from a center of each the stars and the plurality of grooves disposed substantially parallel to each other such that a diffractive light illusion of three-dimensions is provided by the metallic film.
To manufacture the metallized rolled web product with stars, any suitable elastomeric base, polymeric substrate, or dielectric material, i.e. electrically insulating material, can be used to receive a metal. For instance, wood, glass, plastic, reaction injection molded urethane, thermoplastic olefins and urethanes, nylon, rubber and polycarbonates can be suitably used. More specifically, plastic pellets, may be extruded as a film and coated with the desired metal such as aluminum, often via vacuum deposition. Also if desired, a polymeric clear coat may be added to the metal layer using conventional techniques, such as casting or doctor-blade applications.
In another aspect of the invention, a method for forming a container with a metallized surface defining a star pattern having an illusion of three-dimensions includes the steps of:
providing a star-shaped die having a plurality of grooves configured for embossing a xe2x80x9cmasterxe2x80x9d or first film;
forming a debossed surface on the first film by contacting the first film with the star-shaped die, the debossed surface complementing the star pattern of the star-shaped die;
forming a metallic plate from a metal bath process by depositing the debossed first film in a metal depositing solution, the metallic plate resulting from the metal bath process having an embossed surface imprinted with the star pattern and configured to be operatively disposed on a pattern roll;
nipping a second film through an embossing nip formed with the metallic plate such that the second film is embossed with the star pattern from the embossed surface;
metallizing the embossed second film in a metallizing chamber;
adhering the metallized embossed second film to a base material; and
forming the carrying material into a container exhibiting a metallized exterior having the illusion of the three-dimensional star pattern.
The container itself is further provided in this invention. The disclosed container has a base layer bonded to a metallized film. Similar to the foregoing embodiment, a plurality of stars are located on the metallized film to exhibit an illusion of three-dimensions (3-D). Each of the stars in this example has five points, each point having a first and a second side depending from a center to a tip of each of the stars. A first plurality of grooves are cut on the first side of a first point and arranged in a direction different from a second plurality of grooves on the second side of the first point. An adjacent plurality of grooves on an adjacent side of an adjacent point are aligned in the direction of the first plurality of grooves. The first plurality of grooves and the adjacent plurality of grooves cooperate to direct ambient light rays relative to the viewer while the second plurality of grooves direct the light rays differently, which contributes to the three-dimensional illusion.